Various forms of trailer-type carriers and vehicles including lowerable load beds have been heretofore provided such as those disclosed in U.S. Pat. Nos. 2,789,714, 2,803,362, 2,923,425, 3,179,271, 3,240,506, 3,335,887.
However, these previously known load carrying structures have not included the most simplified structure possible with spring mounted running gear whereby heavy farm implements may be readily transported over relatively rough terrain without excessive ground shocks being transmitted to the carrier or the load supported therefrom. The above mentioned U.S. Pat. No. 3,179,271 includes many of the general structural features of the instant invention, but does not include spring mounted running gear nor outwardly and downwardly retractable upstanding sides for retaining a load on the carrier against transverse displacement therefrom.